"No matter what the headlines say … American business is going to do fine over time," Buffett told Judy Woodruff of PBS NewsHour in 2017. "Occasionally we go off the tracks with bubbles … but it will never permanently derail us."

In fact, when he bought his first stock in 1942, the headlines didn't look good, he noted: "We were losing the war in the Pacific."

Markets go up and down every day, but that doesn't necessarily mean there's significance to every move. As an investor, it helps to be patient and to accept a certain level of uncertainty.

Adam Jeffery | CNBC

Warren Buffett, Chairman and CEO of Berkshire Hathaway.

Since buying his first stock, 77 years have gone by and, in all those years, "I've never known what the market is going to do the next day," Buffett said. "That's not my game. My game is to decide whether I'm in the right economy, which America has definitely been ever since that time."

Rather than trying to time your investments, buy and hold for the long term, Buffett tells CNBC. It's what he's been doing since the 1940s and what he still does today, regardless of the headlines.

"I've owned stocks consistently since 1942," Buffett told Woodruff. "I was buying stocks the day before the [2016] election. I was buying stocks the same day after the election. Had Hillary been elected, it would've been the same thing."